This invention relates to a printing head and more particularly to a thermal printing head.
Thick-film thermal printing heads in use today have resistive members secured on a ceramic substrate which are connected to a common conductive member and respective conductive members, both being also secured on such substrate. These thick-film printing heads use a substrate that has a relatively high thermal conductivity which causes a high proportion of available heat to be wasted and not transferred to the paper. A layer of insulating material can be applied onto the substrate under the resistors to impede the heat loss, but this is an extra processing step which adds complexity and cost.
The longitudinal configuration of normally-printed thick-film resistive members is typically undulating such that the center area, where the highest concentration of heat is located, is disposed lower than areas on each side thereof, thereby preventing proper printing on the thermally-sensitive paper.